//
// Copyright (c) 2020 Hiroshi Kimura(Muukii) <muukii.app@gmail.com>
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

import Foundation

final class BackgroundDeallocationQueue {

  private let queue = DispatchQueue.init(label: "org.VergeGroup.deallocQueue", qos: .background)

  private var buffer: ContiguousArray<Unmanaged<AnyObject>> = .init()

  private let lock = NSLock()

  func releaseObjectInBackground(object: AnyObject) {

    let innerCurrentRef = Unmanaged.passRetained(object)

    lock.lock()

    let isFirstEntry = buffer.isEmpty
    buffer.append(innerCurrentRef)

    lock.unlock()

    if isFirstEntry {
      queue.asyncAfter(deadline: .now() + 0.1) {
        self.drain()
      }
    }
  }

  func drain() {

    lock.lock()
    let block = buffer
    buffer = .init()
    lock.unlock()

    for pointer in block {
      pointer.release()
    }

  }
}
